Water heating unit for gas-heated water boiler

ABSTRACT

A plurality of water conducting hollow members are assembled side by side and are interconnected by water ducts to enable water to circulate therethrough. Tie bars pass through the water ducts and have ends projecting through the end walls of the assembled hollow members, the tie bar ends being received in, and affixed to, sockets whereby the assembled members are anchored by the tie bars between the sockets to form a hot water radiator unit. Tie members clasp the side walls of the unit, the tie members being U-shaped elements having free ends with notches and the hollow members having ribs engaged by the notches.

United States Patent 1 Viessmann 1 Mar. 26, 1974 [76] Inventor: I-Ians Viessmann, Battenberg, Eder im l-lain, Germany [22] Filed: Mar. 1, 1973 [21] Appl. No; 337,179

Primary Examiner-Kenneth W. Sprague Assistant Examiner-Larry l. Schwartz Attorney, Agent, or Firm-Kurt Kelman [5 7] ABSTRACT A plurality of water conducting hollow members are assembled side by side and are interconnected by water ducts to enable water to circulate therethrough. Tie bars pass through the water ducts and have ends projecting through the end walls of the assembled hollow members, the tie bar ends being received in, and affixed to, sockets whereby the assembled members are anchored by the tie bars between the sockets to form a hot water radiator unit. Tie members clasp the side walls of the unit, the tie members being U-shaped elements having free ends with notches and the hollow members having ribs engaged by the notches.

6 Claims, 7 Drawing Figures PATENTEDHARZS m4 I SHEET 1 OF 3 PATENTEBMRZB I974 SHEET 3 BF 3 WATER HEATING UNIT FOR GAS-HEATED WATER BOILER The present invention relates to improvements in the mounting of water conducting hollow members assemblcd side by side to form a water heating unit in a gasheated water boiler.

Gas-heated water boilers with a gas burner Operating at atmospheric pressure are known. Such a boiler usually comprises a housing of cylindrical or rectangular cross section erected with a vertical axis and comprising a water conducting outer wall or jacket, a gas burner in communication with the atmosphere being mounted in a lower section of the housing. Suitable spaced from the burner, heat exchange elements are mounted in the housing. The heat exchange elements may be non-water conducting inserts with heat exchange fins in contact with water conducting elements or water conducting radiator elements in communication with the water conducting housing jacket. The heat exchange elements extend vertically in the shaft of the boiler and define channels for the heating gases for escape of the gases from the boiler housing.

Such boilers may be operated at relatively low temperatures causing the gases to condense on the elements. The condensation water may corrode the heat exchange elements.

To overcome this problem and to provide an efficient water boiler of the indicated type, it has been proposed to mount two water conducting outer walls spaced from each other to define therebetween a heating gas shaft or stack, the two walls being interconnected at their lower ends below the gas burner which is mounted between the walls to develop a stream of heating gases moving upwardly through the shaft between the two walls. A plurality of water conducting hollow radiator members are assembled side by side between the two outer walls in the shaft above the burner, each hollow member consisting of a pair of like dished elements having thin walls of corrosion-resistant stainless steel, each pair of dished elements being combined to form mirror images of each other. The dished elements of each pair are welded together in their plane of symmetry along their outer edges and adjacent hollow members define channel therebetween to permit the heating gas to pass therethrough from the burner to a flue. During stamping, the dished elements are also provided with ducts and, during assembly of the hollow members in side-by-side relationship, the ducts of adjacent elements are telescoped into each other and welded together to form a water conducting duct interconnecting the hollow members to enable water to circulate therethrough. Ribs are stamped into the walls of the elements of the hollow members which define the gas conducting channels therebetween, and these ribs are arranged in mutually supporting relationship.

Since the walls of the hollow water conducting members are quite thin, i.e. of the order of about one to two millimeters, problems have been encountered in making such structures resistant to fluid pressure.

To make the heat exchange surfaces pressure resistant, it has been proposed to use support bolts or to press the heat exchange surfaces together at certain points and to spot weld these points together. However, this is rather difficult when the hollow members are made of stainless steel and the internal cavity of the members is rather large to prevent encrustation. Also, welding should be avoided as much as possible in stainless steel structures. Furthermore, special skills are required for welding fluid tight seams. Where there are leaks, it is not possible to weld again.

It is the primary object of the present invention to avoid the above and other difficulties and to provide a superior mounting and anchoring of hollow water conducting members in a water boiler of the indicated type. This and other objects are accomplished in accordance with this invention by passing tie bars through the water ducts. The tie bars have ends projecting through the end walls of the assembled water conducting hollow members and sockets receive the ends of the tie bars. The tie bar ends are affixed to the sockets whereby the assembled hollow members are anchored by the tie bars between the sockets. Tie members clasp the side walls of the assembled hollow members, the

tie members being U-shaped elements having free ends with notches and the hollow members having ribs engaged by the notches.

The tie bars are flat steel strips whose width is equal to the diameter of the ducts through which they pass. They may be spot welded or welded along short seams spaced from each other to the inner wall of the ducts. This produces a good welded connected and a good distribution of the tensile forces. In this manner, the tie bars completely absorb the pressure of the hot water circulating through the ducts.

The ribs of the hollow members, whichv receive the notched ends of the tie members which are clasped about the outside of the assembled hollow members, are provided by the seams along which the two dished elements of each pair are welded to form each hollow member.

Particularly when the walls of the hollow members are of relatively large dimension, outward expansion of the side walls under the internal water pressure may be prevented by welding to the end walls of the assembled members a network of horizontally and vertically extending straps extending between the sockets, the sockets forming the points of intersection in the network. In this case, a grid of relatively small diameter water conducting ducts may be provided, which improves the water circulation and the heat exchange.

The above and other objects, advantages and features of the present invention will become more apparent from the following detailed description of certain now preferred embodiments thereof, taken in conjunction with the accompanying drawing-therein:

FIG. 1 is a side elevational view ofa water boiler unit;

FIG. 2 is a front elevational view of the unit of FIG.

FIG. 3 is a top plan view of this boiler unit; FIG. 4 is a side elevational view of another embodiment of a water boiler unit according to this invention;

. heating unit is shown to comprise a pair of waterconducting hollow outer walls 2, 2 wherebetween there are mounted a plurality of water conducting hollow members 3, a pair of water ducts 4, 4 interconnecting the walls 2 and members 3 to enable water to circulate through the walls and members which form the unit. Each water conducting hollow heating unit member 3 consists of a pair of like dished elements whose walls are of corrosion-resistant stainless steel and which are combined so as to form mirror images of each other. Facing walls 1 of adjacent hollow members 3 constitute heat exchange surfaces and define channels therebetween through which the heating gases rise from gas burner 22 mounted below the members 3 and receiving heating gas through connection 23.

According to the invention, the individual members of the water heating unit are anchored together in the following manner:

Tie bars 6 in the form of flat metal sheets extend through the water ducts 4, 4 and have their ends 8, 8 seam welded to sockets 9 into whose interiors the tie bars project, the sockets 9 being arranged on the water jackets or walls 3.

Tie members 7 extend perpendicularly to tie bars 6 and consist of U-shaped elements whose two free ends 11 have a plurality of notches 12 engaging ribs 13 extending in the plane of symmetry of each water conducting member 3 so that the two members 7 are clasped about the assembly of members 3 under tension. At least the ends of tie members 7 are fixedly connected to the respective members 3.

In the embodiment of FIGS. 4 and 5, intersecting diagonal straps l6 interconnect the free ends 14, 14 of the two tie members 7, the straps extending along the outer surfaces 15 of the water conducting members and being mounted perpendicularly projecting therefrom.

The embodiment of FIGS. 6 and 7 has a grid of nine water ducts interconnecting the water conducting members 3, with tie bars passing through all of the ducts and being mounted in the same manner in sockets 9 as the two tie bars of the previously described embodiments. In addition, there is provided a network of mutually perpendicular straps, the straps 17 extending vertically between sockets 9 while the horizontally extending straps are formed by hollow ducts l8, 18, the upper ducts 18 leading to water inlet 20 and the lower ducts 18 leading to water outlet 21.

These hollowducts are so arranged that they form two forks grasping the unitized members 3 therebetween along their upper and lower edges, connecting ducts l9, 19 extending from the tines of the forks to the water inlet and outlet, respectively. In this arrangement, ducts 18 have two functions, i.e. they operate to hold the unit together and to provide inlets and outlets for the water circulating therethrough. The ends 8 of the tie bars 6 may also be connected to the schematically illustrated ducts 18.

The sockets 9 are water-tightly closed unless they are connected to the water inlet or outlet.

The thermally insulating housing for the gas-heated water boiler unit of this invention is conventional and has not been illustrated. As indicated in broken lines in FIG. 4, this housing has a flue above the water heating unit to enable the heating gases to escape.

What is claimed is:

1. A water heating unit comprising 1. a plurality of water conducting hollow members assembled side by side, each member consisting of a pair of like dished elements having thin walls of corrosion-resistant stainless steel, each pair of dished elements being combined to form mirror images of each other, the assembled hollow members having two opposite end walls and two opposite side walls substantially perpendicular thereto,

2. water ducts interconnecting the hollow members to enable water to circulate therethrough, and the water ducts passing from one of the end walls to the other end wall,

3. tie bars passing through the water ducts and having end projecting through the end walls,

4. sockets receiving the ends of the tie bars, the tie bar ends being affixed to the sockets whereby the assembled hollow members are anchored by the tie bars between the sockets, and

5. tie members clasping the side walls of the assembled hollow members, the tie members being U- shaped elements having free ends with notches, the hollow members having ribs engaged by the notches.

2. The water heating unit of claim 1, further comprising straps interconnecting the free ends of the U- shaped elements and extending along the side walls.

3. The water heating unit of claim 1, further comprising straps interconnecting the sockets and extending along the side walls.

4. The water heating unit of claim 3, wherein at least some of the straps are constituted by hollow ducts.

5. The water heating unit of claim 4, wherein the ho]- low straps are connected to a water inlet and outlet, respectively.

6. The water heating unit of claim 5, wherein the hollow straps form forks clasping the side walls of the assembled hollow members. 

2. The water heating unit of claim 1, further comprising straps interconnecting the free eNds of the U-shaped elements and extending along the side walls.
 2. water ducts interconnecting the hollow members to enable water to circulate therethrough, and the water ducts passing from one of the end walls to the other end wall,
 3. tie bars passing through the water ducts and having end projecting through the end walls,
 3. The water heating unit of claim 1, further comprising straps interconnecting the sockets and extending along the side walls.
 4. The water heating unit of claim 3, wherein at least some of the straps are constituted by hollow ducts.
 4. sockets receiving the ends of the tie bars, the tie bar ends being affixed to the sockets whereby the assembled hollow members are anchored by the tie bars between the sockets, and
 5. tie members clasping the side walls of the assembled hollow members, the tie members being U-shaped elements having free ends with notches, the hollow members having ribs engaged by the notches.
 5. The water heating unit of claim 4, wherein the hollow straps are connected to a water inlet and outlet, respectively.
 6. The water heating unit of claim 5, wherein the hollow straps form forks clasping the side walls of the assembled hollow members. 